I am going to top post...so flame me. Hi Hi. Bob, I'm over 65, been a ham for almost 50 years dropped out of engineering to become a political scientist and somehow or the other became a program manager for ADPE (automatic data processing equipment and systems...can you say computer?).
I will retire on 31 Mar and plan to go back to school and re-take most of the undergraduate level math I too and then advanced math. But by t he time I get through, SDR design will probably the old technology. What I can do today is be what political scientist, economist and business studies call a "business advisor". In other words, I can tell you want the customer wants and how you can get the technical requirements and technical data to provide what the customer wants. SDR and digital communications should be spoken of in the same breath. While I REALLY like the SDR-1000, I cannot for the life of me figure out how to run it with Linux...Bob's instructions are over my head and I don't think that Gerald understands them either. But be that as it may, I will eventually get an SRD-1000 and control it with Linux even if I have to send my computer to Frank and pay him to load the software on it. Hi Hi. I would like to see boxed modules to build an SDR receiver and transmitter, modulator, amps, etc. But that discussion for another day. Everything I have read and experienced leads me to believe that you might need 2 or 3 different "modes" for every band. Any modem needs to have the capability/capabilities that Bob states...and probably even more. It really needs to be adaptive. Ideally the big hit would be a modem that could provide for HF as well as have some V/UHF usefulness. Why hams with a Kenwood D-700 will run only 1200 baud AX.25 when the radio will do 9800 bps AX.25 is beyond me. I don't like ALE...it takes away from the fun of calling CQ. Hi Hi. Thanks for your and Frank's and Bonnie's input...and Frank, I am looking for a CD or DVD that has the Paul whiteman band with Gershwin at the piano playing "Rhapsody in Blue" A 40's RCA 78 RPM record. My copy was stolen but I have the RCA jacket. :-) 73 all, Walt/K5YFW Robert McGwier wrote: > > > My entry in the $10,000 prize hunt will be this wide or wider. ;-) > > Bonnie is, as usual, out in front of most other people's thinking, > leading, goading, etc. AB2KT and I have written the software defined > radio code for SDR-1000 (and others) and we are working on the library > code that will enable this. It has been my interpretation of the rules, > and the interpretation of all my low friends in high places in states > that begin with a "C" , that it is in fact allowed (none willing to > speak on the record). As SDR working group chairman, I have been > actively pursuing these questions and goading development, both hardware > and software. All that is necessary to do this type of modem work in > hardware will probably spring into existence "as if by magic" at Dayton > in the SDR, TAPR, and HFPACK forums. ;-). We need buy in from the > amateur community at large so lots of work needs to be done in the area > of peaceful coexistence but without an exemplar to work with, all you > get is knee jerk reactions on all sides. I will be providing the > exemplar and aiding OTHERS to develop the networks. I simply will not > have the time to do this personally. I challenge Bonnie, Walt, and > others to take what comes and use it and figure out HOW it should be > used. As a scientist/engineer, I will do the technical work, and aid > the policy decisions, but will not make them. > > Here are my current working plans. OFDM, ARBITRARY bandwidth, > variable number of carriers, variable baudrate, BICM or Turbo Trellis > coded modulation DESIGNED FOR the fading channel, ARQ DESIGNED FOR THE > ENVIRONMENT, ...... and to provide this in a format that will allow us > to be radio amateurs: EXPERIMENTATION to figure out the optimal settings > and usable bandwidths. But 18 kHz will NOT be the limitation in the > software. Antennas usable over large frequency ranges will be. NVIS > for this will be an important portion of this. Frank and I have this > goal of having credible "local area networks" that cover thousands of > square miles for all sorts of noble purposes (Emergencies, > infrastructure where none exists or is currently impossible, etc. ) > > There has been a tremendous volume of research, good work, definitely > applicable, which has been done in the last two decades. It is kind of > a shame that you need to have a book budget that is in the thousands of > dollars to put together the library for this work since they are > typically captured in usable form in these expensive books. I am very > fortunate to have this resource provided to me at work. You can get the > work in papers but it is usually so terse as to be difficult even to > professionals with the necessary training. > > Bonnie's leadership in ALE, prodding and poking both the developer and > the users is a critical resource here. ALE is absolutely required to > make this resource usable in my opinion. It will be an enabling > technology in this along with the new SDR code is about to be sprung. > The modem and open source ALE will follow after along with lots of new > SDR capable hardware about the same time. > > QRX > > Bob > N4HY > > Andrew O'Brien wrote: > > So, , what digital modes exist that are in the 12 to 20 kHz range > > could I use if I when and bought a SDR today ? > > Andy K3UK > > > > On 1/24/07, expeditionradio <expeditionradio@ yahoo.com > <mailto:expeditionradio%40yahoo.com>> wrote: > >> > >> SDRs Open the Possibility for 18kHz Bandwidth HF Data > >> providing more robust communications and higher speed data. > >> > >> With new Software Defined Radio (SDR) transceivers that use > >> computer audio as the IF and DSP for filtering and modem, > >> wider bandwidths than the traditional 3kHz SSB transceivers > >> are possible. > >> > >> 12kHz or 20kHz BW is certainly within the range of SDRs. > >> This opens the possibility for some very fast and/or robust > >> HF digital modes that can take advantage of wider bandwidths > >> when needed, or could scale down and up in speed or bandwidth > >> depending upon propagation conditions and need to coexist and > >> share with other spectrum users. > >>
